The electrical efficiency of photovoltaic panels declines if their operating temperature is too high. Cooling technologies, such as water cooling or phase change material cooling, can maintain the efficiency of photovoltaic panels. But these common techniques are expensive and unsuitable for large-scale applications in power stations.
Zhou et al. proposed and tested a low-cost alternative cooling method for photovoltaic power stations: a stepped, multilayer arrangement of the photovoltaic panels. They studied how a double-layer and triple-layer arrangement affect heat dissipation and power generation efficiency compared to a single-layer arrangement.
The authors found the multilayer arrangements lowered the average temperature of the photovoltaic panels more than the single-layer arrangement, suggesting this method is an economical way to effectively cool a ground-mounted, solar-tracking photovoltaic system.
The gaps between the stepped panels increased the flow velocity, which promoted convective heat transfer to cool the photovoltaic systems. The gaps cooled the panels by allowing them to make more contact with incoming low temperature air. The stepped triple-layer arrangement protects the middle and upper rows of panels from the high-temperature wake zone caused by the lower row of the panels, further encouraging heat dissipation.
The triple-layer arrangement cooled the panels the best out of the three arrangements. Under a wind speed of 3 meters per second, the triple-layer arrangement reduced the temperature by more than 6 kelvins, increasing the photoelectric conversion efficiency and output power.
To further facilitate heat dissipation of a photovoltaic system, the authors will consider how to increase the heat dissipation of multiple components of a power station.
Source: “A comparative investigation of the cooling effect of multi-layer arrangements of panels in a ground-mounted photovoltaic system,” by Chenyang Zhou, Wenpei Sun, Min Wang, Jinping Luo, and Lijun Liu, Journal of Renewable and Sustainable Energy (2021). The article can be accessed at https://aip.scitation.org/doi/full/10.1063/5.0058861.